<!DOCTYPE html><html lang="en"><head><link rel="stylesheet" href="./style.css"><title>Adapter - 30 seconds of code</title><meta charset="utf-8"><meta name="description" content="Curated collection of useful Javascript snippets that you can understand in 30 seconds or less."><meta name="keywords" content="javascript, snippets, code, programming"><meta name="author" content="Angelos Chalaris (chalarangelo@gmail.com)"><meta name="viewport" content="width=device-width,initial-scale=1"><meta name="theme-color" content="#111"><meta property="og:title" content="30 seconds of code"><meta property="og:description" content="Curated collection of useful Javascript snippets that you can understand in 30 seconds or less."/><meta property="og:type" content="website"/><meta property="og:image" content="https://30secondsofcode.org/logos/logo_512.png"><link rel="icon" type="image/png" href="./logos/logo_128.png"><link rel="manifest" href="manifest.json"><script>const search = (node) => {
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216.3,84.9 216.3,84.9 C212.7,93.1 206.9,96.0 205.4,96.6 C205.1,102.4 203.0,107.8 198.3,112.5 C181.9,128.9 168.3,122.5 157.7,114.1 C157.9,116.9 156.7,120.9 152.7,124.9 L141.0,136.5 C139.8,137.7 141.6,141.9 141.8,141.8 Z" fill="currentColor" class="octo-body"></path></svg></a><button class="menu-button"></button><header><h1 class="logo"><a href="./index"><img src="https://30secondsofcode.org/logos/logo_256.png" alt="logo"/><span id="title">&nbsp;30 seconds of code</span> <small>Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.</small></a></h1></header><div class="container card-container"><input class="search" type="search" id="searchInput" onkeyup="search(this)" placeholder="Search..." aria-label="Snippet search"><nav><h4 class="collapse">Adapter</h4><ul><li><a tags="adapter,function,intermediate" href="#ary">ary</a></li><li><a tags="adapter,function,intermediate" href="#call">call</a></li><li><a tags="adapter,function,array,intermediate" href="#collectinto">collectInto</a></li><li><a tags="adapter,function,intermediate" href="#flip">flip</a></li><li><a tags="adapter,function,intermediate" href="#over">over</a></li><li><a tags="adapter,function,intermediate" href="#overargs">overArgs</a></li><li><a tags="adapter,function,promise,intermediate" href="#pipeasyncfunctions">pipeAsyncFunctions</a></li><li><a tags="adapter,function,intermediate" href="#pipefunctions">pipeFunctions</a></li><li><a tags="adapter,function,promise,intermediate" href="#promisify">promisify</a></li><li><a tags="adapter,function,intermediate" href="#rearg">rearg</a></li><li><a tags="adapter,intermediate" href="#spreadover">spreadOver</a></li><li><a tags="adapter,function,intermediate" href="#unary">unary</a></li></ul><h4 class="collapse">Array</h4><ul><li><a tags="array,function,beginner" href="./index#all">all</a></li><li><a tags="array,function,beginner" href="./index#allequal">allEqual</a></li><li><a tags="array,function,beginner" href="./index#any">any</a></li><li><a tags="array,string,utility,intermediate" href="./index#arraytocsv">arrayToCSV</a></li><li><a tags="array,intermediate" href="./index#bifurcate">bifurcate</a></li><li><a tags="array,function,intermediate" href="./index#bifurcateby">bifurcateBy</a></li><li><a tags="array,intermediate" href="./index#chunk">chunk</a></li><li><a tags="array,beginner" href="./index#compact">compact</a></li><li><a tags="array,object,intermediate" href="./index#countby">countBy</a></li><li><a tags="array,intermediate" href="./index#countoccurrences">countOccurrences</a></li><li><a tags="array,recursion,intermediate" href="./index#deepflatten">deepFlatten</a></li><li><a tags="array,math,beginner" href="./index#difference">difference</a></li><li><a tags="array,function,intermediate" href="./index#differenceby">differenceBy</a></li><li><a tags="array,function,intermediate" href="./index#differencewith">differenceWith</a></li><li><a tags="array,beginner" href="./index#drop">drop</a></li><li><a tags="array,beginner" href="./index#dropright">dropRight</a></li><li><a tags="array,function,intermediate" href="./index#droprightwhile">dropRightWhile</a></li><li><a tags="array,function,intermediate" href="./index#dropwhile">dropWhile</a></li><li><a tags="array,beginner" href="./index#everynth">everyNth</a></li><li><a tags="array,beginner" href="./index#filternonunique">filterNonUnique</a></li><li><a tags="array,function,intermediate" href="./index#filternonuniqueby">filterNonUniqueBy</a></li><li><a tags="array,beginner" href="./index#findlast">findLast</a></li><li><a tags="array,function,intermediate" href="./index#findlastindex">findLastIndex</a></li><li><a tags="array,intermediate" href="./index#flatten">flatten</a></li><li><a tags="array,function,intermediate" href="./index#foreachright">forEachRight</a></li><li><a tags="array,object,intermediate" href="./index#groupby">groupBy</a></li><li><a tags="array,beginner" href="./index#head">head</a></li><li><a tags="array,intermediate" href="./index#indexofall">indexOfAll</a></li><li><a tags="array,beginner" href="./index#initial">initial</a></li><li><a tags="array,intermediate" href="./index#initialize2darray">initialize2DArray</a></li><li><a tags="array,math,intermediate" href="./index#initializearraywithrange">initializeArrayWithRange</a></li><li><a tags="array,math,intermediate" href="./index#initializearraywithrangeright">initializeArrayWithRangeRight</a></li><li><a tags="array,math,intermediate" href="./index#initializearraywithvalues">initializeArrayWithValues</a></li><li><a tags="array,recursion,intermediate" href="./index#initializendarray">initializeNDArray</a></li><li><a tags="array,math,intermediate" href="./index#intersection">intersection</a></li><li><a tags="array,function,intermediate" href="./index#intersectionby">intersectionBy</a></li><li><a tags="array,function,intermediate" href="./index#intersectionwith">intersectionWith</a></li><li><a tags="array,intermediate" href="./index#issorted">isSorted</a></li><li><a tags="array,intermediate" href="./index#join">join</a></li><li><a tags="array,string,object,advanced" href="./index#jsontocsv">JSONtoCSV</a></li><li><a tags="array,beginner" href="./index#last">last</a></li><li><a tags="array,string,utility,intermediate" href="./index#longestitem">longestItem</a></li><li><a tags="array,object,advanced" href="./index#mapobject">mapObject</a></li><li><a tags="array,math,beginner" href="./index#maxn">maxN</a></li><li><a tags="array,math,beginner" href="./index#minn">minN</a></li><li><a tags="array,function,beginner" href="./index#none">none</a></li><li><a tags="array,beginner" href="./index#nthelement">nthElement</a></li><li><a tags="array,beginner" href="./index#offset">offset</a></li><li><a tags="array,object,function,intermediate" href="./index#partition">partition</a></li><li><a tags="array,recursion,advanced" href="./index#permutations">permutations</a></li><li><a tags="array,intermediate" href="./index#pull">pull</a></li><li><a tags="array,advanced" href="./index#pullatindex">pullAtIndex</a></li><li><a tags="array,advanced" href="./index#pullatvalue">pullAtValue</a></li><li><a tags="array,function,advanced" href="./index#pullby">pullBy</a></li><li><a tags="array,intermediate" href="./index#reducedfilter">reducedFilter</a></li><li><a tags="array,function,intermediate" href="./index#reducesuccessive">reduceSuccessive</a></li><li><a tags="array,function,intermediate" href="./index#reducewhich">reduceWhich</a></li><li><a tags="array,beginner" href="./index#reject">reject</a></li><li><a tags="array,intermediate" href="./index#remove">remove</a></li><li><a tags="array,random,beginner" href="./index#sample">sample</a></li><li><a tags="array,random,intermediate" href="./index#samplesize">sampleSize</a></li><li><a tags="array,intermediate" href="./index#shank">shank</a></li><li><a tags="array,random,intermediate" href="./index#shuffle">shuffle</a></li><li><a tags="array,math,beginner" href="./index#similarity">similarity</a></li><li><a tags="array,math,intermediate" href="./index#sortedindex">sortedIndex</a></li><li><a tags="array,math,function,intermediate" href="./index#sortedindexby">sortedIndexBy</a></li><li><a tags="array,math,intermediate" href="./index#sortedlastindex">sortedLastIndex</a></li><li><a tags="array,math,function,intermediate" href="./index#sortedlastindexby">sortedLastIndexBy</a></li><li><a tags="array,sort,advanced,intermediate" href="./index#stablesort">stableSort</a></li><li><a tags="array,math,intermediate" href="./index#symmetricdifference">symmetricDifference</a></li><li><a tags="array,function,intermediate" href="./index#symmetricdifferenceby">symmetricDifferenceBy</a></li><li><a tags="array,function,intermediate" href="./index#symmetricdifferencewith">symmetricDifferenceWith</a></li><li><a tags="array,beginner" href="./index#tail">tail</a></li><li><a tags="array,beginner" href="./index#take">take</a></li><li><a tags="array,intermediate" href="./index#takeright">takeRight</a></li><li><a tags="array,function,intermediate" href="./index#takerightwhile">takeRightWhile</a></li><li><a tags="array,function,intermediate" href="./index#takewhile">takeWhile</a></li><li><a tags="array,intermediate" href="./index#tohash">toHash</a></li><li><a tags="array,math,beginner" href="./index#union">union</a></li><li><a tags="array,function,intermediate" href="./index#unionby">unionBy</a></li><li><a tags="array,function,intermediate" href="./index#unionwith">unionWith</a></li><li><a tags="array,beginner" href="./index#uniqueelements">uniqueElements</a></li><li><a tags="array,function,intermediate" href="./index#uniqueelementsby">uniqueElementsBy</a></li><li><a tags="array,function,intermediate" href="./index#uniqueelementsbyright">uniqueElementsByRight</a></li><li><a tags="array,math,intermediate" href="./index#uniquesymmetricdifference">uniqueSymmetricDifference</a></li><li><a tags="array,intermediate" href="./index#unzip">unzip</a></li><li><a tags="array,function,advanced" href="./index#unzipwith">unzipWith</a></li><li><a tags="array,beginner" href="./index#without">without</a></li><li><a tags="array,math,intermediate" href="./index#xprod">xProd</a></li><li><a tags="array,intermediate" href="./index#zip">zip</a></li><li><a tags="array,object,intermediate" href="./index#zipobject">zipObject</a></li><li><a tags="array,function,advanced" href="./index#zipwith">zipWith</a></li></ul><h4 class="collapse">Browser</h4><ul><li><a tags="browser,array,intermediate" href="./browser#arraytohtmllist">arrayToHtmlList</a></li><li><a tags="browser,intermediate" href="./browser#bottomvisible">bottomVisible</a></li><li><a tags="browser,string,advanced" href="./browser#copytoclipboard">copyToClipboard</a></li><li><a tags="browser,advanced" href="./browser#counter">counter</a></li><li><a tags="browser,utility,beginner" href="./browser#createelement">createElement</a></li><li><a tags="browser,event,advanced" href="./browser#createeventhub">createEventHub</a></li><li><a tags="browser,url,beginner" href="./browser#currenturl">currentURL</a></li><li><a tags="browser,intermediate" href="./browser#detectdevicetype">detectDeviceType</a></li><li><a tags="browser,intermediate" href="./browser#elementcontains">elementContains</a></li><li><a tags="browser,advanced" href="./browser#elementisvisibleinviewport">elementIsVisibleInViewport</a></li><li><a tags="browser,intermediate" href="./browser#getscrollposition">getScrollPosition</a></li><li><a tags="browser,css,beginner" href="./browser#getstyle">getStyle</a></li><li><a tags="browser,css,beginner" href="./browser#hasclass">hasClass</a></li><li><a tags="browser,utility,advanced,promise,advanced" href="./browser#hashbrowser">hashBrowser</a></li><li><a tags="browser,css,beginner" href="./browser#hide">hide</a></li><li><a tags="browser,url,intermediate" href="./browser#httpsredirect">httpsRedirect</a></li><li><a tags="browser,beginner" href="./browser#insertafter">insertAfter</a></li><li><a tags="browser,beginner" href="./browser#insertbefore">insertBefore</a></li><li><a tags="browser,beginner" href="./browser#isbrowsertabfocused">isBrowserTabFocused</a></li><li><a tags="browser,array,beginner" href="./browser#nodelisttoarray">nodeListToArray</a></li><li><a tags="browser,event,advanced" href="./browser#observemutations">observeMutations</a></li><li><a tags="browser,event,intermediate" href="./browser#off">off</a></li><li><a tags="browser,event,intermediate" href="./browser#on">on</a></li><li><a tags="browser,event,advanced" href="./browser#onuserinputchange">onUserInputChange</a></li><li><a tags="browser,utility,intermediate" href="./browser#prefix">prefix</a></li><li><a tags="browser,utility,intermediate" href="./browser#recordanimationframes">recordAnimationFrames</a></li><li><a tags="browser,url,beginner" href="./browser#redirect">redirect</a></li><li><a tags="browser,function,advanced,promise,url" href="./browser#runasync">runAsync</a></li><li><a tags="browser,intermediate" href="./browser#scrolltotop">scrollToTop</a></li><li><a tags="browser,beginner" href="./browser#setstyle">setStyle</a></li><li><a tags="browser,css,beginner" href="./browser#show">show</a></li><li><a tags="browser,css,intermediate" href="./browser#smoothscroll">smoothScroll</a></li><li><a tags="browser,beginner" href="./browser#toggleclass">toggleClass</a></li><li><a tags="browser,event,intermediate" href="./browser#triggerevent">triggerEvent</a></li><li><a tags="browser,utility,random,intermediate" href="./browser#uuidgeneratorbrowser">UUIDGeneratorBrowser</a></li></ul><h4 class="collapse">Date</h4><ul><li><a tags="date,beginner" href="./date#dayofyear">dayOfYear</a></li><li><a tags="date,math,string,utility,intermediate" href="./date#formatduration">formatDuration</a></li><li><a tags="date,intermediate" href="./date#getcolontimefromdate">getColonTimeFromDate</a></li><li><a tags="date,intermediate" href="./date#getdaysdiffbetweendates">getDaysDiffBetweenDates</a></li><li><a tags="date,beginner" href="./date#getmeridiemsuffixofinteger">getMeridiemSuffixOfInteger</a></li><li><a tags="date,utility,beginner" href="./date#isafterdate">isAfterDate</a></li><li><a tags="date,utility,beginner" href="./date#isbeforedate">isBeforeDate</a></li><li><a tags="date,utility,beginner" href="./date#issamedate">isSameDate</a></li><li><a tags="date,math,beginner" href="./date#maxdate">maxDate</a></li><li><a tags="date,math,beginner" href="./date#mindate">minDate</a></li><li><a tags="date,intermediate" href="./date#tomorrow">tomorrow</a></li></ul><h4 class="collapse">Function</h4><ul><li><a tags="function,intermediate" href="./function#attempt">attempt</a></li><li><a tags="function,object,intermediate" href="./function#bind">bind</a></li><li><a tags="function,object,intermediate" href="./function#bindkey">bindKey</a></li><li><a tags="function,intermediate" href="./function#chainasync">chainAsync</a></li><li><a tags="function,intermediate" href="./function#compose">compose</a></li><li><a tags="function,intermediate" href="./function#composeright">composeRight</a></li><li><a tags="function,intermediate" href="./function#converge">converge</a></li><li><a tags="function,recursion,intermediate" href="./function#curry">curry</a></li><li><a tags="function,intermediate" href="./function#debounce">debounce</a></li><li><a tags="function,intermediate" href="./function#defer">defer</a></li><li><a tags="function,intermediate" href="./function#delay">delay</a></li><li><a tags="function,utility,beginner" href="./function#functionname">functionName</a></li><li><a tags="function,intermediate" href="./function#hz">hz</a></li><li><a tags="function,advanced" href="./function#memoize">memoize</a></li><li><a tags="function,beginner" href="./function#negate">negate</a></li><li><a tags="function,intermediate" href="./function#once">once</a></li><li><a tags="function,intermediate" href="./function#partial">partial</a></li><li><a tags="function,intermediate" href="./function#partialright">partialRight</a></li><li><a tags="function,promise,intermediate" href="./function#runpromisesinseries">runPromisesInSeries</a></li><li><a tags="function,promise,intermediate" href="./function#sleep">sleep</a></li><li><a tags="function,advanced" href="./function#throttle">throttle</a></li><li><a tags="function,intermediate" href="./function#times">times</a></li><li><a tags="function,intermediate" href="./function#uncurry">uncurry</a></li><li><a tags="function,array,intermediate" href="./function#unfold">unfold</a></li><li><a tags="function,intermediate" href="./function#when">when</a></li></ul><h4 class="collapse">Math</h4><ul><li><a tags="math,beginner" href="./math#approximatelyequal">approximatelyEqual</a></li><li><a tags="math,array,beginner" href="./math#average">average</a></li><li><a tags="math,array,function,intermediate" href="./math#averageby">averageBy</a></li><li><a tags="math,intermediate" href="./math#binomialcoefficient">binomialCoefficient</a></li><li><a tags="math,beginner" href="./math#clampnumber">clampNumber</a></li><li><a tags="math,beginner" href="./math#degreestorads">degreesToRads</a></li><li><a tags="math,array,beginner" href="./math#digitize">digitize</a></li><li><a tags="math,beginner" href="./math#distance">distance</a></li><li><a tags="math,array,advanced" href="./math#elo">elo</a></li><li><a tags="math,recursion,beginner" href="./math#factorial">factorial</a></li><li><a tags="math,array,beginner" href="./math#fibonacci">fibonacci</a></li><li><a tags="math,recursion,beginner" href="./math#gcd">gcd</a></li><li><a tags="math,intermediate" href="./math#geometricprogression">geometricProgression</a></li><li><a tags="math,beginner" href="./math#hammingdistance">hammingDistance</a></li><li><a tags="math,beginner" href="./math#inrange">inRange</a></li><li><a tags="math,beginner" href="./math#isdivisible">isDivisible</a></li><li><a tags="math,beginner" href="./math#iseven">isEven</a></li><li><a tags="math,beginner,intermediate" href="./math#isprime">isPrime</a></li><li><a tags="math,recursion,beginner" href="./math#lcm">lcm</a></li><li><a tags="math,utility,advanced" href="./math#luhncheck">luhnCheck</a></li><li><a tags="math,array,function,beginner" href="./math#maxby">maxBy</a></li><li><a tags="math,array,intermediate" href="./math#median">median</a></li><li><a tags="math,array,function,beginner" href="./math#minby">minBy</a></li><li><a tags="math,intermediate" href="./math#percentile">percentile</a></li><li><a tags="math,beginner" href="./math#powerset">powerset</a></li><li><a tags="math,array,intermediate" href="./math#primes">primes</a></li><li><a tags="math,beginner" href="./math#radstodegrees">radsToDegrees</a></li><li><a tags="math,utility,random,intermediate" href="./math#randomintarrayinrange">randomIntArrayInRange</a></li><li><a tags="math,utility,random,beginner" href="./math#randomintegerinrange">randomIntegerInRange</a></li><li><a tags="math,utility,random,beginner" href="./math#randomnumberinrange">randomNumberInRange</a></li><li><a tags="math,intermediate" href="./math#round">round</a></li><li><a tags="math,utility,intermediate" href="./math#sdbm">sdbm</a></li><li><a tags="math,array,intermediate" href="./math#standarddeviation">standardDeviation</a></li><li><a tags="math,array,beginner" href="./math#sum">sum</a></li><li><a tags="math,array,function,intermediate" href="./math#sumby">sumBy</a></li><li><a tags="math,intermediate" href="./math#sumpower">sumPower</a></li><li><a tags="math,beginner" href="./math#tosafeinteger">toSafeInteger</a></li></ul><h4 class="collapse">Node</h4><ul><li><a tags="node,string,utility,beginner" href="./node#atob">atob</a></li><li><a tags="node,string,utility,beginner" href="./node#btoa">btoa</a></li><li><a tags="node,utility,string,intermediate" href="./node#colorize">colorize</a></li><li><a tags="node,intermediate" href="./node#hasflags">hasFlags</a></li><li><a tags="node,utility,promise,intermediate" href="./node#hashnode">hashNode</a></li><li><a tags="node,type,intermediate" href="./node#isduplexstream">isDuplexStream</a></li><li><a tags="node,type,intermediate" href="./node#isreadablestream">isReadableStream</a></li><li><a tags="node,type,intermediate" href="./node#isstream">isStream</a></li><li><a tags="node,intermediate" href="./node#istravisci">isTravisCI</a></li><li><a tags="node,type,intermediate" href="./node#iswritablestream">isWritableStream</a></li><li><a tags="node,json,intermediate" href="./node#jsontofile">JSONToFile</a></li><li><a tags="node,array,string,beginner" href="./node#readfilelines">readFileLines</a></li><li><a tags="node,string,beginner" href="./node#untildify">untildify</a></li><li><a tags="node,utility,random,intermediate" href="./node#uuidgeneratornode">UUIDGeneratorNode</a></li></ul><h4 class="collapse">Object</h4><ul><li><a tags="object,function,intermediate" href="./object#bindall">bindAll</a></li><li><a tags="object,recursion,intermediate" href="./object#deepclone">deepClone</a></li><li><a tags="object,recursion,intermediate" href="./object#deepfreeze">deepFreeze</a></li><li><a tags="object,intermediate" href="./object#defaults">defaults</a></li><li><a tags="object,recursion,intermediate" href="./object#dig">dig</a></li><li><a tags="object,array,type,advanced" href="./object#equals">equals</a></li><li><a tags="object,function,intermediate" href="./object#findkey">findKey</a></li><li><a tags="object,function,intermediate" href="./object#findlastkey">findLastKey</a></li><li><a tags="object,recursion,intermediate" href="./object#flattenobject">flattenObject</a></li><li><a tags="object,intermediate" href="./object#forown">forOwn</a></li><li><a tags="object,intermediate" href="./object#forownright">forOwnRight</a></li><li><a tags="object,function,intermediate" href="./object#functions">functions</a></li><li><a tags="object,intermediate" href="./object#get">get</a></li><li><a tags="object,function,intermediate" href="./object#invertkeyvalues">invertKeyValues</a></li><li><a tags="object,intermediate" href="./object#lowercasekeys">lowercaseKeys</a></li><li><a tags="object,function,intermediate" href="./object#mapkeys">mapKeys</a></li><li><a tags="object,function,intermediate" href="./object#mapvalues">mapValues</a></li><li><a tags="object,type,intermediate" href="./object#matches">matches</a></li><li><a tags="object,type,function,intermediate" href="./object#matcheswith">matchesWith</a></li><li><a tags="object,array,intermediate" href="./object#merge">merge</a></li><li><a tags="object,intermediate" href="./object#nest">nest</a></li><li><a tags="object,array,beginner" href="./object#objectfrompairs">objectFromPairs</a></li><li><a tags="object,array,beginner" href="./object#objecttopairs">objectToPairs</a></li><li><a tags="object,array,intermediate" href="./object#omit">omit</a></li><li><a tags="object,array,function,intermediate" href="./object#omitby">omitBy</a></li><li><a tags="object,array,intermediate" href="./object#orderby">orderBy</a></li><li><a tags="object,array,intermediate" href="./object#pick">pick</a></li><li><a tags="object,array,function,intermediate" href="./object#pickby">pickBy</a></li><li><a tags="object,intermediate" href="./object#renamekeys">renameKeys</a></li><li><a tags="object,beginner" href="./object#shallowclone">shallowClone</a></li><li><a tags="object,array,string,intermediate" href="./object#size">size</a></li><li><a tags="object,array,intermediate" href="./object#transform">transform</a></li><li><a tags="object,logic,array,intermediate" href="./object#truthcheckcollection">truthCheckCollection</a></li><li><a tags="object,advanced" href="./object#unflattenobject">unflattenObject</a></li></ul><h4 class="collapse">String</h4><ul><li><a tags="string,beginner" href="./string#bytesize">byteSize</a></li><li><a tags="string,array,intermediate" href="./string#capitalize">capitalize</a></li><li><a tags="string,regexp,intermediate" href="./string#capitalizeeveryword">capitalizeEveryWord</a></li><li><a tags="string,array,utility,intermediate" href="./string#csvtoarray">CSVToArray</a></li><li><a tags="string,array,object,advanced" href="./string#csvtojson">CSVToJSON</a></li><li><a tags="string,array,intermediate" href="./string#decapitalize">decapitalize</a></li><li><a tags="string,browser,regexp,intermediate" href="./string#escapehtml">escapeHTML</a></li><li><a tags="string,regexp,intermediate" href="./string#escaperegexp">escapeRegExp</a></li><li><a tags="string,intermediate" href="./string#fromcamelcase">fromCamelCase</a></li><li><a tags="string,utility,beginner" href="./string#indentstring">indentString</a></li><li><a tags="string,utility,browser,url,intermediate" href="./string#isabsoluteurl">isAbsoluteURL</a></li><li><a tags="string,regexp,intermediate" href="./string#isanagram">isAnagram</a></li><li><a tags="string,utility,beginner" href="./string#islowercase">isLowerCase</a></li><li><a tags="string,utility,beginner" href="./string#isuppercase">isUpperCase</a></li><li><a tags="string,array,function,utility,beginner" href="./string#mapstring">mapString</a></li><li><a tags="string,utility,regexp,intermediate" href="./string#mask">mask</a></li><li><a tags="string,beginner" href="./string#pad">pad</a></li><li><a tags="string,intermediate" href="./string#palindrome">palindrome</a></li><li><a tags="string,intermediate" href="./string#pluralize">pluralize</a></li><li><a tags="string,regexp,intermediate" href="./string#removenonascii">removeNonASCII</a></li><li><a tags="string,array,beginner" href="./string#reversestring">reverseString</a></li><li><a tags="string,beginner" href="./string#sortcharactersinstring">sortCharactersInString</a></li><li><a tags="string,beginner" href="./string#splitlines">splitLines</a></li><li><a tags="string,recursion,advanced" href="./string#stringpermutations">stringPermutations</a></li><li><a tags="string,utility,regexp,beginner" href="./string#striphtmltags">stripHTMLTags</a></li><li><a tags="string,regexp,intermediate" href="./string#tocamelcase">toCamelCase</a></li><li><a tags="string,regexp,intermediate" href="./string#tokebabcase">toKebabCase</a></li><li><a tags="string,regexp,intermediate" href="./string#tosnakecase">toSnakeCase</a></li><li><a tags="string,beginner" href="./string#truncatestring">truncateString</a></li><li><a tags="string,browser,beginner" href="./string#unescapehtml">unescapeHTML</a></li><li><a tags="string,utility,regexp,advanced" href="./string#urljoin">URLJoin</a></li><li><a tags="string,regexp,intermediate" href="./string#words">words</a></li></ul><h4 class="collapse">Type</h4><ul><li><a tags="type,beginner" href="./type#gettype">getType</a></li><li><a tags="type,array,regexp,beginner" href="./type#is">is</a></li><li><a tags="type,array,intermediate" href="./type#isarraylike">isArrayLike</a></li><li><a tags="type,beginner" href="./type#isboolean">isBoolean</a></li><li><a tags="type,array,object,string,beginner" href="./type#isempty">isEmpty</a></li><li><a tags="type,function,beginner" href="./type#isfunction">isFunction</a></li><li><a tags="type,beginner" href="./type#isnil">isNil</a></li><li><a tags="type,beginner" href="./type#isnull">isNull</a></li><li><a tags="type,math,beginner" href="./type#isnumber">isNumber</a></li><li><a tags="type,object,beginner" href="./type#isobject">isObject</a></li><li><a tags="type,object,beginner" href="./type#isobjectlike">isObjectLike</a></li><li><a tags="type,object,intermediate" href="./type#isplainobject">isPlainObject</a></li><li><a tags="type,function,array,string,intermediate" href="./type#isprimitive">isPrimitive</a></li><li><a tags="type,function,promise,intermediate" href="./type#ispromiselike">isPromiseLike</a></li><li><a tags="type,string,beginner" href="./type#isstring">isString</a></li><li><a tags="type,beginner" href="./type#issymbol">isSymbol</a></li><li><a tags="type,beginner" href="./type#isundefined">isUndefined</a></li><li><a tags="type,json,intermediate" href="./type#isvalidjson">isValidJSON</a></li></ul><h4 class="collapse">Utility</h4><ul><li><a tags="utility,array,type,beginner" href="./utility#castarray">castArray</a></li><li><a tags="utility,regexp,intermediate" href="./utility#cloneregexp">cloneRegExp</a></li><li><a tags="utility,beginner" href="./utility#coalesce">coalesce</a></li><li><a tags="utility,intermediate" href="./utility#coalescefactory">coalesceFactory</a></li><li><a tags="utility,string,intermediate" href="./utility#extendhex">extendHex</a></li><li><a tags="utility,browser,string,url,intermediate" href="./utility#geturlparameters">getURLParameters</a></li><li><a tags="utility,string,math,advanced" href="./utility#hextorgb">hexToRGB</a></li><li><a tags="utility,url,browser,intermediate" href="./utility#httpget">httpGet</a></li><li><a tags="utility,url,browser,intermediate" href="./utility#httppost">httpPost</a></li><li><a tags="utility,browser,intermediate" href="./utility#isbrowser">isBrowser</a></li><li><a tags="utility,function" href="./utility#mostperformant">mostPerformant</a></li><li><a tags="utility,function,beginner" href="./utility#ntharg">nthArg</a></li><li><a tags="utility,string,intermediate" href="./utility#parsecookie">parseCookie</a></li><li><a tags="utility,string,math,advanced" href="./utility#prettybytes">prettyBytes</a></li><li><a tags="utility,random,beginner" href="./utility#randomhexcolorcode">randomHexColorCode</a></li><li><a tags="utility,intermediate" href="./utility#rgbtohex">RGBToHex</a></li><li><a tags="utility,string,intermediate" href="./utility#serializecookie">serializeCookie</a></li><li><a tags="utility,beginner" href="./utility#timetaken">timeTaken</a></li><li><a tags="utility,intermediate" href="./utility#tocurrency">toCurrency</a></li><li><a tags="utility,math,beginner" href="./utility#todecimalmark">toDecimalMark</a></li><li><a tags="utility,math,intermediate" href="./utility#toordinalsuffix">toOrdinalSuffix</a></li><li><a tags="utility,math,intermediate" href="./utility#validatenumber">validateNumber</a></li><li><a tags="utility,regexp,intermediate" href="./utility#yesno">yesNo</a></li></ul><h4 class="static-link"><a href="./archive">Archive</a></h4><h4 class="static-link"><a href="./glossary">Glossary</a></h4><h4 class="static-link"><a href="./contributing">Contributing</a></h4><h4 class="static-link"><a href="./about">About</a></h4><div><button class="social fb"></button><button class="social instagram"></button><button class="social twitter"></button></div></nav><main class="col-centered"><span id="top"><br/><br/></span><h2 class="category-name">Adapter</h2><div class="card code-card"><div class="corner intermediate"></div><div class="section card-content"><h4 id="ary">ary</h4><p>Creates a function that accepts up to <code>n</code> arguments, ignoring any additional arguments.</p><p>Call the provided function, <code>fn</code>, with up to <code>n</code> arguments, using <code>Array.prototype.slice(0,n)</code> and the spread operator (<code>...</code>).</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">ary</span> <span class="token operator">=</span> <span class="token punctuation">(</span>fn<span class="token punctuation">,</span> n<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">(</span><span class="token operator">...</span>args<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token function">fn</span><span class="token punctuation">(</span><span class="token operator">...</span>args<span class="token punctuation">.</span><span class="token function">slice</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span> n<span class="token punctuation">));</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token keyword">const</span> firstTwoMax <span class="token operator">=</span> <span class="token function">ary</span><span class="token punctuation">(</span>Math<span class="token punctuation">.</span>max<span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">);
[[</span><span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">6</span><span class="token punctuation">,</span> <span class="token string">'a'</span><span class="token punctuation">], [</span><span class="token number">8</span><span class="token punctuation">,</span> <span class="token number">4</span><span class="token punctuation">,</span> <span class="token number">6</span><span class="token punctuation">], [</span><span class="token number">10</span><span class="token punctuation">]].</span><span class="token function">map</span><span class="token punctuation">(</span>x <span class="token operator">=></span> <span class="token function">firstTwoMax</span><span class="token punctuation">(</span><span class="token operator">...</span>x<span class="token punctuation">));</span> <span class="token comment">// [6, 8, 10]</span>
</pre></div><div class="card code-card"><div class="corner intermediate"></div><div class="section card-content"><h4 id="call">call</h4><p>Given a key and a set of arguments, call them when given a context. Primarily useful in composition.</p><p>Use a closure to call a stored key with stored arguments.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">call</span> <span class="token operator">=</span> <span class="token punctuation">(</span>key<span class="token punctuation">,</span> <span class="token operator">...</span>args<span class="token punctuation">)</span> <span class="token operator">=></span> context <span class="token operator">=></span> context<span class="token punctuation">[</span>key<span class="token punctuation">](</span><span class="token operator">...</span>args<span class="token punctuation">);</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js">Promise<span class="token punctuation">.</span><span class="token function">resolve</span><span class="token punctuation">([</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">])
  .</span><span class="token function">then</span><span class="token punctuation">(</span><span class="token function">call</span><span class="token punctuation">(</span><span class="token string">'map'</span><span class="token punctuation">,</span> x <span class="token operator">=></span> <span class="token number">2</span> <span class="token operator">*</span> x<span class="token punctuation">))
  .</span><span class="token function">then</span><span class="token punctuation">(</span>console<span class="token punctuation">.</span>log<span class="token punctuation">);</span> <span class="token comment">//[ 2, 4, 6 ]</span>
<span class="token keyword">const</span> map <span class="token operator">=</span> call<span class="token punctuation">.</span><span class="token function">bind</span><span class="token punctuation">(</span><span class="token keyword">null</span><span class="token punctuation">,</span> <span class="token string">'map'</span><span class="token punctuation">);</span>
Promise<span class="token punctuation">.</span><span class="token function">resolve</span><span class="token punctuation">([</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">])
  .</span><span class="token function">then</span><span class="token punctuation">(</span><span class="token function">map</span><span class="token punctuation">(</span>x <span class="token operator">=></span> <span class="token number">2</span> <span class="token operator">*</span> x<span class="token punctuation">))
  .</span><span class="token function">then</span><span class="token punctuation">(</span>console<span class="token punctuation">.</span>log<span class="token punctuation">);</span> <span class="token comment">//[ 2, 4, 6 ]</span>
</pre></div><div class="card code-card"><div class="corner intermediate"></div><div class="section card-content"><h4 id="collectinto">collectInto</h4><p>Changes a function that accepts an array into a variadic function.</p><p>Given a function, return a closure that collects all inputs into an array-accepting function.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">collectInto</span> <span class="token operator">=</span> fn <span class="token operator">=></span> <span class="token punctuation">(</span><span class="token operator">...</span>args<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token function">fn</span><span class="token punctuation">(</span>args<span class="token punctuation">);</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token keyword">const</span> Pall <span class="token operator">=</span> <span class="token function">collectInto</span><span class="token punctuation">(</span>Promise<span class="token punctuation">.</span>all<span class="token punctuation">.</span><span class="token function">bind</span><span class="token punctuation">(</span>Promise<span class="token punctuation">));</span>
<span class="token keyword">let</span> p1 <span class="token operator">=</span> Promise<span class="token punctuation">.</span><span class="token function">resolve</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">);</span>
<span class="token keyword">let</span> p2 <span class="token operator">=</span> Promise<span class="token punctuation">.</span><span class="token function">resolve</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">);</span>
<span class="token keyword">let</span> p3 <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Promise</span><span class="token punctuation">(</span>resolve <span class="token operator">=></span> <span class="token function">setTimeout</span><span class="token punctuation">(</span>resolve<span class="token punctuation">,</span> <span class="token number">2000</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">));</span>
<span class="token function">Pall</span><span class="token punctuation">(</span>p1<span class="token punctuation">,</span> p2<span class="token punctuation">,</span> p3<span class="token punctuation">).</span><span class="token function">then</span><span class="token punctuation">(</span>console<span class="token punctuation">.</span>log<span class="token punctuation">);</span> <span class="token comment">// [1, 2, 3] (after about 2 seconds)</span>
</pre></div><div class="card code-card"><div class="corner intermediate"></div><div class="section card-content"><h4 id="flip">flip</h4><p>Flip takes a function as an argument, then makes the first argument the last.</p><p>Return a closure that takes variadic inputs, and splices the last argument to make it the first argument before applying the rest.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">flip</span> <span class="token operator">=</span> fn <span class="token operator">=></span> <span class="token punctuation">(</span>first<span class="token punctuation">,</span> <span class="token operator">...</span>rest<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token function">fn</span><span class="token punctuation">(</span><span class="token operator">...</span>rest<span class="token punctuation">,</span> first<span class="token punctuation">);</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token keyword">let</span> a <span class="token operator">=</span> <span class="token punctuation">{</span> name<span class="token punctuation">:</span> <span class="token string">'John Smith'</span> <span class="token punctuation">};</span>
<span class="token keyword">let</span> b <span class="token operator">=</span> <span class="token punctuation">{};</span>
<span class="token keyword">const</span> mergeFrom <span class="token operator">=</span> <span class="token function">flip</span><span class="token punctuation">(</span>Object<span class="token punctuation">.</span>assign<span class="token punctuation">);</span>
<span class="token keyword">let</span> mergePerson <span class="token operator">=</span> mergeFrom<span class="token punctuation">.</span><span class="token function">bind</span><span class="token punctuation">(</span><span class="token keyword">null</span><span class="token punctuation">,</span> a<span class="token punctuation">);</span>
<span class="token function">mergePerson</span><span class="token punctuation">(</span>b<span class="token punctuation">);</span> <span class="token comment">// == b</span>
b <span class="token operator">=</span> <span class="token punctuation">{};</span>
Object<span class="token punctuation">.</span><span class="token function">assign</span><span class="token punctuation">(</span>b<span class="token punctuation">,</span> a<span class="token punctuation">);</span> <span class="token comment">// == b</span>
</pre></div><div class="card code-card"><div class="corner intermediate"></div><div class="section card-content"><h4 id="over">over</h4><p>Creates a function that invokes each provided function with the arguments it receives and returns the results.</p><p>Use <code>Array.prototype.map()</code> and <code>Function.prototype.apply()</code> to apply each function to the given arguments.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">over</span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token operator">...</span>fns<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">(</span><span class="token operator">...</span>args<span class="token punctuation">)</span> <span class="token operator">=></span> fns<span class="token punctuation">.</span><span class="token function">map</span><span class="token punctuation">(</span>fn <span class="token operator">=></span> fn<span class="token punctuation">.</span><span class="token function">apply</span><span class="token punctuation">(</span><span class="token keyword">null</span><span class="token punctuation">,</span> args<span class="token punctuation">));</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token keyword">const</span> minMax <span class="token operator">=</span> <span class="token function">over</span><span class="token punctuation">(</span>Math<span class="token punctuation">.</span>min<span class="token punctuation">,</span> Math<span class="token punctuation">.</span>max<span class="token punctuation">);</span>
<span class="token function">minMax</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">,</span> <span class="token number">4</span><span class="token punctuation">,</span> <span class="token number">5</span><span class="token punctuation">);</span> <span class="token comment">// [1,5]</span>
</pre></div><div class="card code-card"><div class="corner intermediate"></div><div class="section card-content"><h4 id="overargs">overArgs</h4><p>Creates a function that invokes the provided function with its arguments transformed.</p><p>Use <code>Array.prototype.map()</code> to apply <code>transforms</code> to <code>args</code> in combination with the spread operator (<code>...</code>) to pass the transformed arguments to <code>fn</code>.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">overArgs</span> <span class="token operator">=</span> <span class="token punctuation">(</span>fn<span class="token punctuation">,</span> transforms<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">(</span><span class="token operator">...</span>args<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token function">fn</span><span class="token punctuation">(</span><span class="token operator">...</span>args<span class="token punctuation">.</span><span class="token function">map</span><span class="token punctuation">((</span>val<span class="token punctuation">,</span> i<span class="token punctuation">)</span> <span class="token operator">=></span> transforms<span class="token punctuation">[</span>i<span class="token punctuation">](</span>val<span class="token punctuation">)));</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token keyword">const</span> <span class="token function-variable function">square</span> <span class="token operator">=</span> n <span class="token operator">=></span> n <span class="token operator">*</span> n<span class="token punctuation">;</span>
<span class="token keyword">const</span> <span class="token function-variable function">double</span> <span class="token operator">=</span> n <span class="token operator">=></span> n <span class="token operator">*</span> <span class="token number">2</span><span class="token punctuation">;</span>
<span class="token keyword">const</span> fn <span class="token operator">=</span> <span class="token function">overArgs</span><span class="token punctuation">((</span>x<span class="token punctuation">,</span> y<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">[</span>x<span class="token punctuation">,</span> y<span class="token punctuation">], [</span>square<span class="token punctuation">,</span> double<span class="token punctuation">]);</span>
<span class="token function">fn</span><span class="token punctuation">(</span><span class="token number">9</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">);</span> <span class="token comment">// [81, 6]</span>
</pre></div><div class="card code-card"><div class="corner intermediate"></div><div class="section card-content"><h4 id="pipeasyncfunctions">pipeAsyncFunctions</h4><p>Performs left-to-right function composition for asynchronous functions.</p><p>Use <code>Array.prototype.reduce()</code> with the spread operator (<code>...</code>) to perform left-to-right function composition using <code>Promise.then()</code>. The functions can return a combination of: simple values, <code>Promise</code>'s, or they can be defined as <code>async</code> ones returning through <code>await</code>. All functions must be unary.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">pipeAsyncFunctions</span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token operator">...</span>fns<span class="token punctuation">)</span> <span class="token operator">=></span> arg <span class="token operator">=></span> fns<span class="token punctuation">.</span><span class="token function">reduce</span><span class="token punctuation">((</span>p<span class="token punctuation">,</span> f<span class="token punctuation">)</span> <span class="token operator">=></span> p<span class="token punctuation">.</span><span class="token function">then</span><span class="token punctuation">(</span>f<span class="token punctuation">),</span> Promise<span class="token punctuation">.</span><span class="token function">resolve</span><span class="token punctuation">(</span>arg<span class="token punctuation">));</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token keyword">const</span> sum <span class="token operator">=</span> <span class="token function">pipeAsyncFunctions</span><span class="token punctuation">(</span>
  x <span class="token operator">=></span> x <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">,</span>
  x <span class="token operator">=></span> <span class="token keyword">new</span> <span class="token class-name">Promise</span><span class="token punctuation">(</span>resolve <span class="token operator">=></span> <span class="token function">setTimeout</span><span class="token punctuation">(()</span> <span class="token operator">=></span> <span class="token function">resolve</span><span class="token punctuation">(</span>x <span class="token operator">+</span> <span class="token number">2</span><span class="token punctuation">),</span> <span class="token number">1000</span><span class="token punctuation">)),</span>
  x <span class="token operator">=></span> x <span class="token operator">+</span> <span class="token number">3</span><span class="token punctuation">,</span>
  <span class="token keyword">async</span> x <span class="token operator">=></span> <span class="token punctuation">(</span><span class="token keyword">await</span> x<span class="token punctuation">)</span> <span class="token operator">+</span> <span class="token number">4</span>
<span class="token punctuation">);
(</span><span class="token keyword">async</span> <span class="token punctuation">()</span> <span class="token operator">=></span> <span class="token punctuation">{</span>
  console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token keyword">await</span> <span class="token function">sum</span><span class="token punctuation">(</span><span class="token number">5</span><span class="token punctuation">));</span> <span class="token comment">// 15 (after one second)</span>
<span class="token punctuation">})();</span>
</pre></div><div class="card code-card"><div class="corner intermediate"></div><div class="section card-content"><h4 id="pipefunctions">pipeFunctions</h4><p>Performs left-to-right function composition.</p><p>Use <code>Array.prototype.reduce()</code> with the spread operator (<code>...</code>) to perform left-to-right function composition. The first (leftmost) function can accept one or more arguments; the remaining functions must be unary.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">pipeFunctions</span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token operator">...</span>fns<span class="token punctuation">)</span> <span class="token operator">=></span> fns<span class="token punctuation">.</span><span class="token function">reduce</span><span class="token punctuation">((</span>f<span class="token punctuation">,</span> g<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">(</span><span class="token operator">...</span>args<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token function">g</span><span class="token punctuation">(</span><span class="token function">f</span><span class="token punctuation">(</span><span class="token operator">...</span>args<span class="token punctuation">)));</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token keyword">const</span> <span class="token function-variable function">add5</span> <span class="token operator">=</span> x <span class="token operator">=></span> x <span class="token operator">+</span> <span class="token number">5</span><span class="token punctuation">;</span>
<span class="token keyword">const</span> <span class="token function-variable function">multiply</span> <span class="token operator">=</span> <span class="token punctuation">(</span>x<span class="token punctuation">,</span> y<span class="token punctuation">)</span> <span class="token operator">=></span> x <span class="token operator">*</span> y<span class="token punctuation">;</span>
<span class="token keyword">const</span> multiplyAndAdd5 <span class="token operator">=</span> <span class="token function">pipeFunctions</span><span class="token punctuation">(</span>multiply<span class="token punctuation">,</span> add5<span class="token punctuation">);</span>
<span class="token function">multiplyAndAdd5</span><span class="token punctuation">(</span><span class="token number">5</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">);</span> <span class="token comment">// 15</span>
</pre></div><div class="card code-card"><div class="corner intermediate"></div><div class="section card-content"><h4 id="promisify">promisify</h4><p>Converts an asynchronous function to return a promise.</p><p>Use currying to return a function returning a <code>Promise</code> that calls the original function. Use the <code>...rest</code> operator to pass in all the parameters.</p><p><em>In Node 8+, you can use <a href="https://nodejs.org/api/util.html#util_util_promisify_original"><code>util.promisify</code></a></em></p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">promisify</span> <span class="token operator">=</span> func <span class="token operator">=></span> <span class="token punctuation">(</span><span class="token operator">...</span>args<span class="token punctuation">)</span> <span class="token operator">=></span>
  <span class="token keyword">new</span> <span class="token class-name">Promise</span><span class="token punctuation">((</span>resolve<span class="token punctuation">,</span> reject<span class="token punctuation">)</span> <span class="token operator">=></span>
    <span class="token function">func</span><span class="token punctuation">(</span><span class="token operator">...</span>args<span class="token punctuation">, (</span>err<span class="token punctuation">,</span> result<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">(</span>err <span class="token operator">?</span> <span class="token function">reject</span><span class="token punctuation">(</span>err<span class="token punctuation">) :</span> <span class="token function">resolve</span><span class="token punctuation">(</span>result<span class="token punctuation">)))
  );</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token keyword">const</span> delay <span class="token operator">=</span> <span class="token function">promisify</span><span class="token punctuation">((</span>d<span class="token punctuation">,</span> cb<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token function">setTimeout</span><span class="token punctuation">(</span>cb<span class="token punctuation">,</span> d<span class="token punctuation">));</span>
<span class="token function">delay</span><span class="token punctuation">(</span><span class="token number">2000</span><span class="token punctuation">).</span><span class="token function">then</span><span class="token punctuation">(()</span> <span class="token operator">=></span> console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'Hi!'</span><span class="token punctuation">));</span> <span class="token comment">// // Promise resolves after 2s</span>
</pre></div><div class="card code-card"><div class="corner intermediate"></div><div class="section card-content"><h4 id="rearg">rearg</h4><p>Creates a function that invokes the provided function with its arguments arranged according to the specified indexes.</p><p>Use <code>Array.prototype.map()</code> to reorder arguments based on <code>indexes</code> in combination with the spread operator (<code>...</code>) to pass the transformed arguments to <code>fn</code>.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">rearg</span> <span class="token operator">=</span> <span class="token punctuation">(</span>fn<span class="token punctuation">,</span> indexes<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">(</span><span class="token operator">...</span>args<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token function">fn</span><span class="token punctuation">(</span><span class="token operator">...</span>indexes<span class="token punctuation">.</span><span class="token function">map</span><span class="token punctuation">(</span>i <span class="token operator">=></span> args<span class="token punctuation">[</span>i<span class="token punctuation">]));</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token keyword">var</span> rearged <span class="token operator">=</span> <span class="token function">rearg</span><span class="token punctuation">(</span>
  <span class="token keyword">function</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> b<span class="token punctuation">,</span> c<span class="token punctuation">) {</span>
    <span class="token keyword">return</span> <span class="token punctuation">[</span>a<span class="token punctuation">,</span> b<span class="token punctuation">,</span> c<span class="token punctuation">];
  },
  [</span><span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">,</span> <span class="token number">1</span><span class="token punctuation">]
);</span>
<span class="token function">rearged</span><span class="token punctuation">(</span><span class="token string">'b'</span><span class="token punctuation">,</span> <span class="token string">'c'</span><span class="token punctuation">,</span> <span class="token string">'a'</span><span class="token punctuation">);</span> <span class="token comment">// ['a', 'b', 'c']</span>
</pre></div><div class="card code-card"><div class="corner intermediate"></div><div class="section card-content"><h4 id="spreadover">spreadOver</h4><p>Takes a variadic function and returns a closure that accepts an array of arguments to map to the inputs of the function.</p><p>Use closures and the spread operator (<code>...</code>) to map the array of arguments to the inputs of the function.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">spreadOver</span> <span class="token operator">=</span> fn <span class="token operator">=></span> argsArr <span class="token operator">=></span> <span class="token function">fn</span><span class="token punctuation">(</span><span class="token operator">...</span>argsArr<span class="token punctuation">);</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token keyword">const</span> arrayMax <span class="token operator">=</span> <span class="token function">spreadOver</span><span class="token punctuation">(</span>Math<span class="token punctuation">.</span>max<span class="token punctuation">);</span>
<span class="token function">arrayMax</span><span class="token punctuation">([</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">]);</span> <span class="token comment">// 3</span>
</pre></div><div class="card code-card"><div class="corner intermediate"></div><div class="section card-content"><h4 id="unary">unary</h4><p>Creates a function that accepts up to one argument, ignoring any additional arguments.</p><p>Call the provided function, <code>fn</code>, with just the first argument given.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">unary</span> <span class="token operator">=</span> fn <span class="token operator">=></span> val <span class="token operator">=></span> <span class="token function">fn</span><span class="token punctuation">(</span>val<span class="token punctuation">);</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token punctuation">[</span><span class="token string">'6'</span><span class="token punctuation">,</span> <span class="token string">'8'</span><span class="token punctuation">,</span> <span class="token string">'10'</span><span class="token punctuation">].</span><span class="token function">map</span><span class="token punctuation">(</span><span class="token function">unary</span><span class="token punctuation">(</span>parseInt<span class="token punctuation">));</span> <span class="token comment">// [6, 8, 10]</span>
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